Temperature stress Flashcards
What processes increase heat generation in the body in response to cold stress
General metabolism
Voluntary muscular actvitiy
Involuntary muscular activity -> shivering
Non-shivering thermogenesis (burning brown fat in infants)
What processes decrease heat loss from the body in response to cold stress
Vasomotor control -> arteriolar constriction
Behavioural response -> putting on clothes, moving to warmer areas…
A body temp below what is diagnostic of hypothermia
<35oC
Who are most at risk of hypothermia
Neonates (not much fat)
Elderly (poor shivering thermogenesis)
Homeless
Cold store & off-shore workers
Outdoor pursuitors
How can you treat hypothermia
Remove wet clothes
Add warm clothes
Insulation
Blankets
Hot drinks
What can occur as a result of severe hypothermia in the peripheries
Frostbite
What are the 2 types of processes that cause frostbite
Vascular processes
Cellular processes
What occurs in the vascular processes that cause frostbite
Vasosonctriction
Thrombosis
Anoxia
Increased blood viscocity
What occurs in the cellular processes that cause frostbite
Formation of ice crystals in the extracellular space
Incresased extraceullar osmolarity, causing water to move from the intracellular space
Leads to anoxia
What are the aims of the body’s response to
a) cold stress
b) heat stress
a) increase body temp
b) decrease body temp
What processes reduce heat production in response to heat stress
Decreased physical activity
Decreased food intake
What processes increase heat loss in response to heat stress
Vasomotor control -> arteriolar dilation
Sweating
Behahvioural response s -> taking off clothes, getting naked
What type of fibres are responsible for sweating and what type of heat loss does it increase
Fibres -> sympathetic cholinergic fibres
Heat loss -> evaporative
What are the treatments for both heat exhaustion and heat stroke
Move to cooloer areas
Remove clothing
Cold air
Sponge with luke-warm water
Fluids (oral or IV)
What are the risk factors for heat stress
Neonates
Elderly
Physical work in hot/humid areas
Wearing non-breathable protective clothing
Give an example of types of:
a) heat illness
b) heat injury
a) heat exhuastion
b) heat stroke
What body temperatures cause:
a) heat exhausation
b) heat stroke
a) >37.5oC
b) >40oC
What processes occur as a result of heat exhaustion
Increased vasodilation
Decreased central blood volume
Excess sweating
Excess sweating often occurs as a result of heat stress, what can it lead to
Distrubance in the body’s salt & fluid balance
What are the symptoms of heat exhaustion
Headache
Confusion
Nausea
Clammy skin
Tachycardia
Hypotension
Loss of consciousness
Profuse sweating
What are the symptoms of heat stroke
Hot & dry skin
Circulatory collapse
Loss of consciousness
No sweating
What is the difference bwteen heat echaustion and heat stroke in terms of sweating
Heat exhaustion -> profuse sweating
Heat stroke -> no sweating
What vasomotor responses occur in response to:
a) cold stress
b) heat stress
a) arteriolar constriction
b) arteriolar dilation
What basic bodily processes occur in respone to cold and heat stress
Cold stress -> shivering
Heat stress -> sweating
